PB2165: BIOINFORMATIC TOOL FOR IMMUNOMODULATING THE ONCOGENIC TRANSCRIPTOME OF ABC-DLBCLS
Authors: M. Rodríguez, J. Cornago, J. Serrano, R. Alonso Alonso, D. Morillo, M. A. Perez Saenz, J. M. Alonso Dominguez, M. A. Piris, J. Sánchez García, P. Llamas Sillero, J. Serrano Lopez
Journal: HemaSphere (2022)

Background: Activated B-cell (ABC) lymphomas emerged as a distinct molecular subtype within Diffuse Large B-Cell Lymphoma (DLBCL). Canonical and non-canonical constitutive activation of nuclear factor kappa B (NF-kB) signaling pathway has been widely reported in the ABCs, and mainly implicates gain-of-function mutations in many players downstream of the BCR receptor. This molecular entity is normally associated with poor clinical outcome after standard immunochemotherapy. The discouraging results obtained in several clinical trials using proteasome inhibitors, tyrosine kinase inhibitors, or immunomodulators, lead to an intense search for new, potentially druggable biomarkers in DLBCL. Immunosuppressive microenvironment is a hallmark in many solid tumors as well as in DLBCLs. Aims: Herein, we searched for bioinformatic tools aim to repurpose drugs capable of modulating immune cells from transcriptomics dataset generated by RNA-seq analysis. Methods: RNA-seq was applied to RNA samples from FFPE blocks of DLBCL patients, 4 of whom were previously classified as GCB and the remaining 4 as ABC, based on NanoString-LST. All ABC were negative for the MYD88L265P mutation (ABC-MYD88non-L265P) determined by allele-specific PCR (AS-PCR). Median of age was 66.5 years (range 40-82) and 71.5 years (range 53-85) for GCB and ABC, respectively. Indexed samples were run together on a NextSeq 500 instrument (Illumina Inc.) with a 2 × 150-bp paired-end protocol. An average of 25.8 million mapped reads was generated per sample. Next, bioinformatic tool DREIMT was utilized to predict drugs for intratumor immunomodulation. DREIMT employ FGSEA ES and Pairwise ES calculations to calculate the enrichment score (ES). P-value estimation is calculated by adaptive multi-level split Monte-Carlo scheme and is P-adjusted using Benjamin correction. DREIMT apply a drug prioritization score (T, tau, ranging +100 to -100) following the approach described by LINCS L1000 team. To consider strong hypotheses for the drug profile-immune gene expression associations, we considered tau> 99 and selected top 26 candidates ranked by tau score. In the same way, we examined tau> -99 and chosen top 26 candidates ranked by tau score Results: We identified 79 differentially expressed genes (DEGs) obtained after RNA-seq analysis. GSEA showed two main enriched routes implicated in metabolism and immune pathways in the ABC lymphomas, tumor suppressor genes (TSGs) as MAPK10 and GRHL1 were downregulated while anti-inflammatory such as ALOX15B was upregulated. Triggers of Th2 response as CHIT1 and CHI3L-1 were upregulated, like serine protease inhibitors SERPINA1 and SERPINA5. The proto-oncogene FRG was upregulated. DREIMT applied on the 79 DEGs interestingly showed its capacity to selected drugs involved in augmenting anti-tumor immune response. Among them, Bucladesine, Labetalol or Glimepiride boost Th1 response and macrophages M1. On the other hand, Moracizine and Voriconazole inhibit of expression of genes encoding inflammatory molecules in monocytes Summary/Conclusion: RNA-sequencing-derived transcriptome described new tumor-resistant genes dysregulated in the ABC-MYD88non-L265P which promote the maintenance of tumor cells. DREIMT enables us to propose a prioritized list of drugs as the best theoretical therapeutic candidates to treat these patients in order to immunomodulating the oncogenic transcriptomic of ABC-DLBCLs. Of note, most of the proposed drugs are not being yet considered in the clinical practice of this cancer subtype opening up the approach of preclinical studies and new treatment possibilities